Emergency lighting



Aug. 15, 1933. E Q DlXQN 1,922,079

EMERGENCY LIGHTING Filed Feb. 9, 1932 AAl HKTU

' Patented Aug. 15, 1933.

s UNITED STATES PATENT GFIC EMERGENCY LIGHTING ldward Dixon, Lakewood, Ohio Application Fe'li'ruary 9, 19312. Serial No. `591,843

'Ihis invention relates to electric. lighting apparatus and more particularly to a novel form of lighting unit which is adapted to be operated by alternating current from the usual .house lighting system, but which is so constructed that it continues to give illumination even though the.

supply of current for the house lighting system may fail from any cause whatsoever.

Lighting apparatus of thiskindmay be-used wherever desired as a general utility light, but is especially suitable for use in-supplying illum-f ination for surgical operations .and diagnostic work where a failure in the usual form of lighting means might be of serious consequence. This apparatus is also especially useful for indicating the location of exits in theaters, school auditoriums, and the like, where failure of the ordinary form of lighting means might be the cause of serious consequences should such failure occur at the time of a iire or other disaster.

Accordingly, the principal object of my invention may be regarded as the provision of a novel form of lighting unit adapted to beoperated from the house lighting circuit and embodying an auxiliary source of power for operating the lamp after the supply of current from the house lighting circuit has been interrupted.

Another object of my invention is the provision of a lighting unit of the type referred to, wherein the supply of current from the auxiliary source of power is automatically established immediately upon the failure of the house lighting current supply so that illumination will be supplied during an emergency without the performance of "any manual acts.

' further object of my invention is to provide a lighting unit of the type referred to, wherein the auxiliary source of power is a storage battery which is housed in a container forming alpart'of the lighting unit, and wherein means is also provided for maintaining the battery in a charged condition.

Further objects and advantages of the invention will be apparent from the following description when taken in conjunction with `the accompanying sheet of drawing, wherein,

Fig. 1 is a side elevation of a lighting u nit constructed according to my invention. l

Fig. 2 is a top plan view thereof.

Fig. 3 is a wiring diagram of my lighting unit, and

Fig. 4 is a wiring diagram of another lighting unit embodying my invention.

In the accompanying drawing, tohwhich detailed reference will now be made, I have shown the preferred 4forms of my lighting unit,- and al- Auniversal movement of the lamp casing.

e claims. -(c1. 24o-11 though. in describing my invention I have referred to this unit as being a form of emergency lighting apparatus suitable for use in operating rooms and for indicating the location of exits from audivtoriums and the like, it should be understood however that the invention may be embodied in various other arrangements and may be put to various other uses.

In its preferredfoim, my lighting unit i's of a portable character and as shown in the drawing, is provided with a baselor carriage 10, having suitable casters 1 1, and constituting a support for a tubular post or pedestal 12 and for the container 13. The lamp itself comprisesa suitably constructed casing 14, which is provided with an efficient reflector and lens in the usual relation, and which embodies a light emitting element, preferably in the form of a low voltage incandescent lamp 15. The lamp casing 14 is adjustably connected to a horizontally disposed supporting rod 15', preferably byv means of a ball and socket joint 16 which permits substanti'ly e rod 15' is slidably adjustable in a supporting head 17 which is carried at the upper end of a vertical and-is rotatable in, the pedestal 12 and may be l readily permit the lamp casing 14 to be extended `into a desired position, as for example, over an operating table or other desired location.

Electric current of suitable characteristics-is supplied to the light emitting element of the lam-p casing through a exible conductor 20 leading from the container 13. This container which, as

stated above, is supported upon the' base 10, mayl be of any suitable shape, but preferably comprises a stationary section 21 and a top section 22 connected to the stationary section by means of the hinges 23. The stationary container section is made of such size and shape. that it will conveniently accommodate a low voltage 4storage battery, while the movable container section is constructed of a size and shape to accommodate other parts of the apparatus for supplying current to the incandescent lamp 15. Theunit is provided with a flexible conductor or extensin cord 24 which may be plugged into the house lighting circuit as the mainsource of power forA operating the device. A switch 25, of suitable construction, may be conveniently located on top of the container section 22 for controlling the operation of the lamp unit.

When the switch 25 has been closed, current is supplied from the house lighting circuit through the conductor 24 to the primary winding 26 of a transformer 25 which is located in the movable container section 22. This transformer may be of any suitable construction, and is here shown as being a stepdown transformer having a secondary winding 27 for supplying low voltage current to the lamp 15 during normal conditions of use, and a secondary winding 28 for supplying charging current to the storage battery 29. The charging current generated in the secondary winding 28 is supplied to the storage battery 29 through a rectifier 30, which may be of any suitable form of construction.

In accordance with my invention, I provide an automatic switch 31, which is preferably located in the movable container section 22, and which is adapted to control the supply of current to the lamp 15 so that the latter is operated from the secondary winding 27 during normal conditions, and is operated from the storage battery 29 whenever the supply of power to the primary of the transformer is interrupted. This automatic switch may be of any suitable form of construction, but since my lighting unit may be used in a room charged with an inammable gas, such as the ether liberated in an operating room, I prefer to use a switch having contacts enclosed so as to prevent such inammable gas from being ignited by electric sparks which may be produced'at this point. The switch provided in this instance' comprises a frame 32 having a magnetizable core 33, and a magnetizing winding 34, which surrounds the core and is energized from the current supply line 24. An armature 35 is pivoted to the frame member 32 for movement away from the core 33 by gravity and toward the core by the magnetic force created by energization of the coil 34. This movable armature carries an envelope 36 which contains a body of conducting liquid, such as mercury, and is provided with pairs of electrodes extending into the envelope for engagement with the body of mercury. This envelope is preferably formed of glass, and as shown in the drawing, is provided at one end thereof with a pair of electrodes 37 and 38 and at its other end with a pair of electrodes 39 and 40. These electrodes extend through, and are sealed into, the wall of the glass envelope, each pair being arranged relatively close--to one end of the envelope so hat when the latter is tilted upon swinging movement ofthe armature," 35, the body of mercury will travel to the lower end of the tube and serve as a conducting medium for establishing an electrical connection between the electrodes of one of the pairs, depending upon the direction in which the armature is swung.

It will be noted that the switch 25 is of the double pole type, and is so connected that the arm 42 thereof controls the circuit for the primary winding of the transformer and the arm 43 thereof is adapted to control the charging circuit for the battery 29 and the circuit for the lamp 15. When this switch is closed to put the lamp in opferation, the primary winding of the transformer is energized and current is immediately induced in the secondarywinding 28 and supplied to the battery 29 through the rectifier 30. The circuit for this charging current may be traced from the secondary 28 through the rectifier 30, and

through conductors 44 and 45 to the arm 43 of the switch 25. From the switch arm 43 this circuit may be traced through conductors 46 and 47 to the battery 29 and thence back to the secondary 28 through conductor 48.

Upon the closing of switch 25, current is also induced in the secondary winding 27, and is supplied by the latter to the filament of the lamp 15 to produce the desired illumination. The circuit for the lament currentl may be traced from the secondary 27 through conductor 46, switch arm 43, and conductors 45 and 49 to the lamp 15. From lamp l5 the circuit is continued through conductor 50, electrodes 39 and 40, and through conductor 5l back to the secondary 27.

Since the winding 34 of the automatic switch 3l is permanently connected across the supply line for the primary winding of the transformer, this coil will be immediately energized upon the closing of the switch 25. The energization of this coil magnetizes the core 33 and causes the armature 35 to be swung about its pivot and moved into engagement with the core. This swinging movement of the armature causes the envelope 36 to assume an inclined position so that the mercury within the envelope travels to that end of the envelope into which the electrodes 39 and 40 extend. The contacting of the mercury with these electrodes completes the circuit for the lamp, connecting the latter in series with the secondary winding 27, and so long as the supply of power to the unit through the conductors 24 is uninterrupted, the lamp will be operated from this secondary winding of the transformer.

Now, should the supply of current being received from the house lighting circuit be suddenly interrupted, as might occur during a storm or the burning out of a fuse, the coil 34 of the automatic switch 31 will be suddenly deenergized. Immediatelyupon the deenergization of this coil the armature 35 drops away from the core 33 under the influence of gravity, causing the envelope 36 to assume the inclined position shown in full lines in Fig. 3. The movement of the envelope to this position causes the mercury therein to travel to the left-hand end of the envelope as seen in this gure, and to contact with the electrodes 37 and 38. This shifting of the mercury within the envelope causes the lamp circuit previously in use to be opened between the terminals 39 and 40, so that the supply of current to the lamp from the secondary winding 27 is cut off, and the contacting of the mercury with the terminals 37 and 38 establishes a second circuit for the lamp whereby the latter is supplied with current from the battery 29. L Should the power supply to the house lighting circuit be reestablished, current will of course again be supplied to the transformer winding 26 and the coil 34 will again be magnetized. Such magnetization of this coil will again shift the armature 35 and cause the lamp circuit to be energized from the transformer winding 27 instead of the battery 29. It will be understood that this shifting of the lamp circuit from the transformer winding 27, as a source of energy, to the battery 29 takes place automatically and entirely independently of any manual act. Likewise the shifting of the lamp circuit from the battery 29 back to the transformer winding 27, also takes place entirely automativ/cally immediately upon the restoration of the main power supply to the house lighting circuit.

In some instances it may be desirable to provide for a continuous charging of the storage battery, which forms the auxiliary source of power for operating the lamp, and to satisfy this condition of operation I employ the wiring circuit illustrated in Fig. 4. In the latter arrangement, the primary winding of the transformer 56 is permanently connected to the house wiring system by means of the conductors 57, and so long as power is available in the house lighting circuit, a charging current will be induced in the secondary winding 58 and supplied to the battery 59 through a suitable rectifier 60. Another secondary. winding 61 may be connected to the lamp 62 by means of the manually operable switch 63 and the automatic switch 64. The latter switch is of the same construction as the automatic switch 8l referred to above, and is provided with a magnetizing winding 65 which is permanently connected .to the supply conductors .57 and, so long as power is available in the house lighting circuit, the coil 65 remains energized. During the time that the coil 65 is energized the movable armature 66 is held in engagement with the core 67, and the envelope 68, which is carried by the armature, is inclined so that the mercury therein engages the electrodes 69 and '70.

When the switch 63 is closed by the operator, as when illumination is required, current is irnrnediately supplied from the secondarywinding 6l for the operation of the lamp, and this operation will continue uninterrupted so long as the supply of power through the conductors 57 is not cut off. Should the supply of-current from the house lighting circuit fail, the winding 65 is immediately deenergized allowing therarmature 66 to drop by gravity to the full line position indicated in Fig. 4. The movement of the armature to this position causes the mercury to move away from the electrodes 69 and 70 and into engagement with the electrodes 71 and 72. The en gagernent of the mercury with the latter electrodes connects the lamp 62 in circuit with the battery 59 so that during 'the time that power is not available from the house lighting circuit, the lamp will be operated from the battery. When power is again available in the house lighting circuit the coil 65 is reenergized, causing the mercury to shift in the envelope 68 and thereby disconnect the lamp 62 from the battery 59, and to reestablish the connection between the lamp and the secondary winding Sl.

From the foregoing description it will be readily seen that I have provided a novel and extremely useful lighting unit which is capable of supplying substantially constantI and uninterrupted illumination even though the lsupply of power tothe house lighting system be temporarily interrupted. It will also be "een that the' shifting of the lamp circuit to the auxiliary power supply during an emergency, and back to .the normal power supply, takes place entirely auto- .inatcally and substantially instantaneously without the requirement of any manual acts. lt is to be noted further, that in my lighting unit the incandescent lamp which supplies the illumination, is of low voltage type so that when operated from a portable storage battery as an auxiliary power source, the intensity of illumination available during the emergency condition will be substantially the same as the intensity of illumination which is availableu during normal operation. the time that the unit is in use, the storage battery is being recharged so that the latter is al- Ways'maintained-in a substantially fully charged state and ready 'for instant use upon the occurrence of an yemergency condition.

Moreover, it will be seen that during While I have illustrated and described the apparatus of my invention in a detailed manner, it should'be understood, however, that I do not intend to limit myself to the precise Jdetails 'of construction and arrangements of parts illustrated and described, but regard my invention as including such changes and modifications as do not depart from the spirit of the invention and the scope of the appended claims.

Having thus described my invention,'I claim: 1. In a portable lighting device adapted to be operated selectively from an alternating current source or from a battery, the combination of a support, a lamp on lsaid support, a sectional container on said support including a stationarycontainer part and another container part associated with said stationary part but movable relative thereto, a storage battery in said stationary container part, a transformer in the movable container part, and automatically operable means in said movable container part for selectively connecting said lamp`for operation from said battery or from said transformer.

2. A portable lighting unit comprising a lamp, a plurality of power sources for supplying energy to said lamp, one of said sources being a supply line and the other source being a storage bat tery, 'means for charging said storage battery, and means responsive to line energization for operatively connecting said lamp for normal operation from said supply line and emergency'operation from the battery. 3. A lighting unit of the character described, comprising a low voltage lamp, a plurality of power sources for supplying energy to said lamp, one of said sources being a transformer energized from an available power line, and the other source being a battery, means for charging said battery from said power line, and switch means ior controlling the energization of said lamp from said sources, said switch means including a magnetv winding connected across said line and contact means responsive to the magnetic action of said winding to normally energize said lamp from said transformer and upon failure of the line power supply to energize said lamp from said battery. n

4. A lighting unit of the character described comprisinga portable container having a lamp support associated therewith, a lamp carried by said support, and means in said container for supplying energy to said lamp, said means comprising a transformer energized from an available power line, a storage battery, and a switch for controlling the energiuzation of said lamp from the energy supplying means, said switch having a magnet winding connected across said line and contact means responsive to the magnetic action of said winding to normally energize said lamp from said transformer and upon failure of the line power supply to energize said lamp from said battery.

5. A lighting unit of the character described,`

comprising a portable container having a lamp support associated therewith, a low voltage lamp carried by said support, and means in said con-v a battery, and switch means for controlling the energization of said lamp from said sources, said switch means having a magnet winding connected across said line, and contact means responsive to the magnetic action of said winding to normally energize said lamp from said transformer and upon failure of power in the house lighting system to energize said lamp from said battery.

EDWARD C. DIXON. 

